Expansion bolt



L. R. ZIFFERER EXPANSION BOLT Aug. 5, 1930.

Filed 'June 14, 1928 Patented ug. 5, 1930 UNITED STATES LOTHAR R. ZIFFERER, OF COLUMBIA, PENNSYLVANIA EXPANSION BOLT Application' filed June 14,

This invention relates to an expansion bolt having a shield with two pivoted sections between which is an expander in the form of a wedge nut. y

The present improvementsv are directed to means for holding a work engaging bolt against movement relative to the expander within the shield, so that eventhough the work should become loose the attaching'bolt therefor will not do likewise, but will remain dependably in the position to which it is originally adjusted.

An exemplilication of my invention is setV forth in the accompanying drawing in the manner following: A

Figure 1 is a viewin elevation of the shield as it appears when first introduced into the hole prepared for its reception in a body of masonry, concrete, or the like;

Fig. 2 is a similar view showing the shield advanced longitudinally to nal position within. the hole, the shield being initially expanded during this movement;

Fig. 3 is a similar view of the shield sections as they appear when further expanded upon application of the work engaging bolt to the expander;

Fig. 4 is a longitudinal section through the shield with the parts positioned about as shown in Fig. 3;

Fig. 5 is an enlarged detail in section of the expander and associated parts; p

Fig. 6 is a transverse section taken 0n line 6 6 of Fig. 4.-; and

Figs. 7 and 8 are vertical sections through the expander, taken in planes in right angular relation.

In a body A. of concrete, masonr, or the like a hole B is provided for the reception of the present expansion bolt which comprises a pair of shield sections C and C substantially alike. One of these sections may be equipped with a pair of lugs 8 which overlaps the other section whereon are provided laterally extending pins 9 extending through apertures in the lugs whereby to establish a pivotal connection between the two sections 'of the Shield. This Connection, a win be noted, is near the outer shield end so as to permit the inner ends of the shield to swing leas. sei-iai No. 285,235.

apart freely a limited distance in response to forces of expansion produced by advance of a. wedge nut D. T his free swinging ,Inovenient'is arrested when the outer ends of the shield sections come together, as shown in Fig. y2. *The outer surfaces of the two shield sections may be provided with ribs 10 and 11 disposed circuinferentially and longitudinally so as to resist longitudinal and rotary moveinents'of the expansion when the shieldV sections'are engaged with the wall surface surrounding the hole B. Y l The interior of each shield section is provided with a concave inclined surface 12 against which the expander exerts an increasing pressure as it is advanced toward the outer end of the expansion. The expander,as best shown in Fig. 6, isin the general form of a truncated cone having an elliptical cross. section whereby to provide tapering sides" 13 adapted to engage with theinclined surfaces 12 upon'the interior ofthe shield sections. For the major portion of its length, the expandei1 is split bythe provision of slots lllwhich, as shown, are arranged oppositely in the plane of its shorterA axis.V Each of vthese slots proceeds from its inner larger end close to the outer smaller end, and may terminate in an enlargement 15 of such character as to facilitate bendingof the two split nut -sections in response to a suflicient force which is vdeveloped for this purpose. The outer smaller end ofthe nut is continuous so as to have vthe form of a collar 16. The nut is threaded interiorly at 17 to cooperate with the screw threads of a bolt E adapted to pass through the work F so as to present the bolt head 18 in engagement therewith. The v,threaded hole which is extended lengthwise of the nut is preferably tapered slightly toward its outer collared end whereby the inner threaded ,sections of the nut are normally vspaced from the threads o f the inner end of the bolt which extends therethrough. It will be noted, by refe'rence'iirst to Fig. 5 and then lto Fig. t, that-as the nut is drawn'into the 'shield between the inclined surfaces 12 that the spaced sections are caused to bendinwardly from the enlarged ends 15 of the slots lhcausing the sections intermediate the ends of the nut to bind upon the sides of the bolt,

Which binding progressively increasesV at this point as the inner spaced portions of the nut are contracted upon the inner threaded end of the bolt, thus offering an increasing resistance to the passage therethrough of the threaded bolt.`

TheV present expansion shield is adapted to be anchored in a hole having a depth slightly in excess of its ovvn length. The expander may initially project'beyond the inner end ofV vthe shield, as shown in Fig. l, thereby causing the outer shield end to protrude from the hole for a s.ight distance. y By ablow from a hammer or other implement the shield'may be driven into the hole to the final longitudinalinto the continuous upper end of the expander Where no appreciable distortion` can take place; As the bolt is screwed further into theexpander, it encounters an increasingfriction oyving to slight taper of the threaded splitl sectionsl ofthe nut. By the application oa sullicient torsional force the bolt Will be ,required to1 pass through the expander as far as necessary', thereby drawing the same outivaordly'when the bolt head 18 engages with the Work. The final position of the expander maybe vvell toward the outer end of the shield eef/faena. depending upon the degree ofY @X- pansion which is required: for producinga secure, anchorage. Y

V e rlilhe present expansion bolt is advantageous on acount of the several features already referredto. t is also capable of expansion to an unusualdegree. The pivoted-outer end of the expansionisunafectedtoanyconsiderable extent by the separation of the two shield sec,- tions, due tothe spreading movement thereofbeing; confined mostlyV to the inner end of the device. In case it becomes necessary to Withdraw the bolt for removal of the Work, thesplit sections of the nut, which may be two or" more, will continue toV remain tightly ivedged against the tapering interior surfaces ofthe shield so as to lprevent collapse of its sections, thereby preserving the parts in condition for yfurther service When the bolt is reintroduced. Also, because of the friction obtainingfbetween the bolt and the expander, the former will not tend to unscrew should the Worlr'become-loose for any reason. lThis ifsfofparticu'lar advantage Where theexpansion is used'to fasten a Vseat to the floor, it beingla common faultl that once the seat starts i@ Worlg loose, the bolt VWill, also tend to loosen mafiosa its hold on the expander until finally it dis-l nut com risinoa luralit ofs aced sectionsv integrally joined at the outer end byva collar and having threads Aformed interiorly of the collar and extending for the length of the several sections of the expander, the axial opening through thevr expander increasing slightly in diameter from the collared end to the ends of the several sections, whereby upon axial movement of the expander into the inclined ends of the shield saidthreaded sections are contracted upon the bolt, progressively increasing resistance to movement of the bolt therebetween.

Y ln testimony whereof I have hereuntofsetV my rand this th day offflrune` 1928. LI ZIFFERER. 

